Medical advisers to the Food and Drug Administration unanimously said Thursday that the agency should approve a
vaccine against a virus that causes cervical cancer.
The FDA advisory committee said the vaccine Gardasil was safe and effective for girls and women between the ages of 9 and 26. The agency isn't bound by its advisers' recommendations, but it usually follows their suggestions. The FDA is scheduled to act on Merck's application by June 8.
If approved, Gardasil would be the first vaccine against human papillomavirus, or HPV. Although there are many types of HPV, Gardasil targets two versions of sexually transmitted HPV that account for a majority of cervical cancer cases. Merck says these two types cause an estimated 70% of cervical cancer cases. That estimate is backed by the National Cancer Institute, although a recent FDA report said these two forms of HPV cause more than 50% of cervical cancer cases.
Gardasil also is designed to combat two types of HPV that account for 90% of genital warts, Merck says.
The committee's vote helped push up Merck's stock 88 cents, or 2.6%, to $35.2 in heavier than average trading by late afternoon. Analysts say the vaccine could achieve sales of $1 billion or more annually in peak years.
Although Gardasil has been granted an accelerated review by the FDA, the agency has been known to take extra time in reviewing first-in-class products. For example, earlier this year, the FDA told Merck it would need an additional 90 days to review the company's application for
Zostavax, the first vaccine against shingles. The agency is scheduled to act on Zostavax by May 25.
Any delay on Gardasil would give
more time to catch up with its Cervarix, a vaccine aimed at the two biggest cervical cancer-causing types of HPV. GlaxoSmithKline expects to file its application with the FDA by the end of the year. In March, it sought European Union approval for Cervarix.
Merck also has submitted Gardasil applications to the EU and to Australia, New Zealand, Mexico, Brazil, Argentina, Singapore and Taiwan. Merck licenses the technology used in Gardasil from
, an Australian drug and vaccine company.
Public Health Impact
The FDA says there will be nearly 10,000 new cervical cancer cases and 3,700 cervical cancer deaths in the U.S. this year. Merck estimates that 20 million American men and women are infected with HPV, although the virus goes away on its own for most people. Worldwide, cervical cancer kills about 300,000 a year.
"Infection with high-risk HPV types increases the chance that mild abnormalities will progress to more severe abnormalities or cervical cancer," says the National Cancer Institute. Having many unprotected sex with many partners raises the risk of getting HPV.
"Studies suggest that whether a woman develops cervical cancer depends on a variety of factors acting together with high-risk HPVs," the institute says. "The factors that may increase the risk of cervical cancer in women with HPV infection include smoking and having many children."
The advisory committee's vote came one day after an FDA staff report said Gardasil was
generally safe and effective. FDA staff members routinely issue report before advisory panels meet, providing data analyses and suggesting questions for panelists to ask during the hearings.
The advisory reviewed an experimental vaccine whose late-stage clinical trial results
encouraged physicians, analysts and investors when Merck released data in October. Merck said Gardasil prevented 100% of high-grade precancerous lesions of the cervix as well as non-invasive cervical cancers.
The study compared Gardasil vs. placebo among women who weren't infected with HPV when they enrolled in the test and remained free of infection while they were vaccinated. They were followed for an average of two years after enrolling. This study tested women ages 16 to 26. They were given three injections of Gardasil or placebo over six months.